Dtrace Userland Project

Rui Paulo has been awarded a grant to add DTrace userland support to FreeBSD.

DTrace is a general purpose and lightweight tracing framework that allows administrators, developers and users to investigate causes of system failure or performance bottlenecks. The FreeBSD operating system has had support for kernel-only DTrace since FreeBSD 8.0, but DTrace userland support was missing. Having userland support in DTrace allows inspection of userland software itself and its correlation with the kernel, thus allowing a much better picture of what exactly is going on behind the scenes.

This project will first concentrate on adding libproc support for symbol to address mapping, address to symbol mapping, breakpoint setup and the rtld interactions with DTrace. Next it will focus on DTrace process control, importing the pid provider and adapting it to FreeBSD and porting the userland statically defined probe provider (usdt). Finally it will bring in the plockstat provider.

“By having userland DTrace support, companies can make their products perform much better on FreeBSD due to the fact that they now have access to this amazing tool,” said FreeBSD developer Rui Paulo. He also said, “When we mix the userland support with the kernel side DTrace support, we can also make FreeBSD a better operating system because we can investigate performance bottlenecks much easier.”

The project should be completed by September 2010.